What strange chess rules can you think up?

Here's one I came up with: The queen in addition to it's current capabilities could make a move like a Knight. However, upon completing this move the queen would be demoted to a pawn. Of course as a pawn it has the chance to be promoted again to a Queen if it reaches the back rank. Or if it makes a knight move that lands on the back rank it simultaneously demotes and promotes so it could become a queen again or any other piece.

Falcon Punch: Once during each game, you may punch your opponent in the nose as hard as you want. If he bleeds on a piece, it is removed from the board. If he gets knocked out, you win the game and his wallet.

Cannibalism: You may remove one of your own pawns that within one square of your knight. The knight then upgrades from a {1,2} leaper to a {3,4} leaper for this turn.

Conversion chamber: Before the game begins, each player writes down a column letter (A through H), which they do not reveal until necessary. If an opponent's pawn promotes on the column you've chosen, the promoted piece becomes your color, not the opponent's.

The rook acts as a block. Nobody except a knight can jump over it - it cuts the lines of pieces. It can never be captured. It captures nothing and does not give check.

Either player, in his move, can choose to move the green rook. It moves like any rook.

A player may not move the green rook in such a way as will undo his opponent previous move! eg if I play green rook e4 to h4, you cannot answer me on your next move, green rook h4 to e4. You can move it anywhere else, or wait for another move, and then put it on e4 if the move is still legal.

No pawn can promote to a second green rook, though. One such barrier is enough. A very old idea of mine, which is nice to tell over these pages. Haven't told many people about it yet..

Battlenet Rigmarole:Before the game begins, each player names a Pokemon, a drug, or a philosopher, and the other player must guess which category it is from. If you correctly guess your opponent's phrase, you may replace a piece of theirs with a pistachio, which can only move one space backwards. If you guess incorrectly, you must play the entire game without pants or underwear, and you must eat a spoonful of baked beans after each move.

When it reaches the 7th rank, it can either stay a pawn and aspire for greater heights, or become a R, N or B (no Q)

and - on reaching the 6th rank, it can either stay a pawn (it cannot change its mind later, unless it marches onward) or become a N or B (no Q or R)

This can revolutionze the game, as suddenly the pawn push to the 6th acquires a new meaning! A new minor piece occupying a hole in attack, or sacrificing itself for tempo gain.

Also the pawn push to the 7th, making a rook, will make many drawn endings suddenly won! (such as, all king and pawn against king endings, where the king blockades but can't capture the pawn, also R+P vs. R endings).

What about if chess was played with exactly the same rules, but the goal was to get your king to the opposite side of the board first (like a pawn promote). Obviously, capturing the king would also win.

Then people would avoid exchanges like wildfire, calculating into a 'winning ending' or 'losing ending' where the board is just too sparse to block a voyaging king...

Then, you can improve it so that the game ends by checkmate, the result being 1-0, or by a 'king promotion', where the result is, say, 5-0.

In some cases you will need to be 'careful' not to checkmate your opponent, so that you can play the king-march... a defensive technique might be to force you to checkmate, just like today there are stalemate traps...

Falcon Punch: Once during each game, you may punch your opponent in the nose as hard as you want. If he bleeds on a piece, it is removed from the board. If he gets knocked out, you win the game and his wallet.

Cannibalism: You may remove one of your own pawns that within one square of your knight. The knight then upgrades from a {1,2} leaper to a {3,4} leaper for this turn.

Conversion chamber: Before the game begins, each player writes down a column letter (A through H), which they do not reveal until necessary. If an opponent's pawn promotes on the column you've chosen, the promoted piece becomes your color, not the opponent's.